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            <div><h3 class="title">
                <a name="asio.reference.execution__start"></a><a class="link" href="execution__start.html"
                                                                 title="execution::start">execution::start</a>
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    <p>
        <a class="indexterm" name="asio.indexterm.execution__start"></a>
    </p>
    <p>
        A customisation point that notifies an operation state object to start its
        associated operation.
    </p>
    <pre class="programlisting"><span class="keyword">constexpr</span> <span class="identifier">unspecified</span> <span
            class="identifier">start</span> <span class="special">=</span> <span
            class="identifier">unspecified</span><span class="special">;</span>
</pre>
    <p>
        The name <code class="computeroutput"><span class="identifier">execution</span><span
            class="special">::</span><span class="identifier">start</span></code> denotes a customisation point object.
        The expression <code class="computeroutput"><span class="identifier">execution</span><span
            class="special">::</span><span class="identifier">start</span><span class="special">(</span><span
            class="identifier">R</span><span class="special">)</span></code>
        for some subexpression <code class="computeroutput"><span class="identifier">R</span></code>
        is expression-equivalent to:
    </p>
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        <ul class="itemizedlist" type="disc">
            <li class="listitem">
                <code class="computeroutput"><span class="identifier">R</span><span class="special">.</span><span
                        class="identifier">start</span><span class="special">()</span></code>,
                if that expression is valid.
            </li>
            <li class="listitem">
                Otherwise, <code class="computeroutput"><span class="identifier">start</span><span
                    class="special">(</span><span class="identifier">R</span><span class="special">)</span></code>,
                if that expression is valid, with overload resolution performed in a
                context that includes the declaration <code class="computeroutput"><span class="keyword">void</span>
                <span class="identifier">start</span><span class="special">();</span></code>
                and that does not include a declaration of <code class="computeroutput"><span class="identifier">execution</span><span
                    class="special">::</span><span class="identifier">start</span></code>.
            </li>
            <li class="listitem">
                Otherwise, <code class="computeroutput"><span class="identifier">execution</span><span class="special">::</span><span
                    class="identifier">start</span><span class="special">(</span><span class="identifier">R</span><span
                    class="special">)</span></code> is ill-formed.
            </li>
        </ul>
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    <h5>
        <a name="asio.reference.execution__start.h0"></a>
        <span><a name="asio.reference.execution__start.requirements"></a></span><a class="link"
                                                                                   href="execution__start.html#asio.reference.execution__start.requirements">Requirements</a>
    </h5>
    <p>
        <span class="emphasis"><em>Header: </em></span><code class="literal">asio/execution/start.hpp</code>
    </p>
    <p>
        <span class="emphasis"><em>Convenience header: </em></span><code class="literal">asio/execution.hpp</code>
    </p>
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            <div class="copyright-footer">Copyright © 2003-2022 Christopher M. Kohlhoff<p>
                Distributed under the Boost Software License, Version 1.0. (See accompanying
                file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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